It is known, according to copending application, Ser. No. 681,358, filed Apr. 29, 1976 now U.S. Pat. No. 4,086,282, that 3,5-xylenol is advantageously prepared by a process which comprises heating isophorone at a temperature of from about 450.degree. C. to about 650.degree. C. in the presence of a homogeneous catalyst comprising a halogen having an atomic number of at least 17 or an organic compound containing such halogen. However, it has been found that this process results in a product xylenol which is contaminated by a residue of free halogen and multiple organic halide compounds. The variety and the chemical nature of such halogen residue compounds do not permit their effective separation from the xylenol product by conventional means such as fractional distillation.
The utility of 3,5-xylenol as a solvent, a disinfectant, an oxidation inhibitor, and an intermediate in chemical synthesis and its use in processes for ore flotation and for production of resins and plastics are well recognized. Many of these potential applications for the 3,5-xylenol produced, as described above, by methods involving a homogeneous halogen catalyst would be precluded unless the halogen residues could be efficiently and effectively removed from the 3,5-xylenol product. Furthermore, it has been found that unless the halogen residues are substantially removed from the product xylenol, the mixture is corrosive to mild steel, thus creating problems in the processing, transport, and storage of the xylenol. For instance, the presence of significant quantities of halogen residues in the reaction product mixture requires that distillation columns for separation of unreacted isophorone and reaction byproducts from the crude 3,5-xylenol must be constructed of expensive corrosion-resistant alloy materials. Therefore, it would be of advantage if a process was available whereby halogen residues could be efficiently and effectively removed from the xylenol product.